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IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Network174.89.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
174.89.0.0
Broadcast address
174.89.127.255
First usable
174.89.0.1
Last usable
174.89.127.254
Usable hosts
32,766 (32,768 less the network and broadcast addresses)
Subnet mask
255.255.128.0
Wildcard mask
0.0.127.255 (Cisco ACLs, OSPF)
Prefix length
/17
Type
Public public
Old class
B (default /16)
As numbers
Hex AE590000 · Integer 2925068288 to 2925101055
Reverse DNS zones
0.89.174.in-addr.arpa
1.89.174.in-addr.arpa
2.89.174.in-addr.arpa
3.89.174.in-addr.arpa
4.89.174.in-addr.arpa
5.89.174.in-addr.arpa
6.89.174.in-addr.arpa
7.89.174.in-addr.arpa
8.89.174.in-addr.arpa
9.89.174.in-addr.arpa
10.89.174.in-addr.arpa
11.89.174.in-addr.arpa
12.89.174.in-addr.arpa
13.89.174.in-addr.arpa
14.89.174.in-addr.arpa
15.89.174.in-addr.arpa
and 112 more
/17 is not on a 8-bit boundary, so it takes 128 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10101110.01011001.00000000.00000000174.89.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network10101110.01011001.00000000.00000000174.89.0.0
Broadcast10101110.01011001.01111111.11111111174.89.127.255
Split into smaller subnets/24
/18 (2)/19 (4)/20 (8)/21 (16)/22 (32)/23 (64)/24 (128)/25 (256)/26 (512)/27 (1,024)/28 (2,048)/29 (4,096)

174.89.0.0/17 makes 128 subnets of /24.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1174.89.0.0/24174.89.0.1 to 174.89.0.254174.89.0.255254
2174.89.1.0/24174.89.1.1 to 174.89.1.254174.89.1.255254
3174.89.2.0/24174.89.2.1 to 174.89.2.254174.89.2.255254
4174.89.3.0/24174.89.3.1 to 174.89.3.254174.89.3.255254
5174.89.4.0/24174.89.4.1 to 174.89.4.254174.89.4.255254
6174.89.5.0/24174.89.5.1 to 174.89.5.254174.89.5.255254
7174.89.6.0/24174.89.6.1 to 174.89.6.254174.89.6.255254
8174.89.7.0/24174.89.7.1 to 174.89.7.254174.89.7.255254
9174.89.8.0/24174.89.8.1 to 174.89.8.254174.89.8.255254
10174.89.9.0/24174.89.9.1 to 174.89.9.254174.89.9.255254
11174.89.10.0/24174.89.10.1 to 174.89.10.254174.89.10.255254
12174.89.11.0/24174.89.11.1 to 174.89.11.254174.89.11.255254
13174.89.12.0/24174.89.12.1 to 174.89.12.254174.89.12.255254
14174.89.13.0/24174.89.13.1 to 174.89.13.254174.89.13.255254
15174.89.14.0/24174.89.14.1 to 174.89.14.254174.89.14.255254
16174.89.15.0/24174.89.15.1 to 174.89.15.254174.89.15.255254
17174.89.16.0/24174.89.16.1 to 174.89.16.254174.89.16.255254
18174.89.17.0/24174.89.17.1 to 174.89.17.254174.89.17.255254
19174.89.18.0/24174.89.18.1 to 174.89.18.254174.89.18.255254
20174.89.19.0/24174.89.19.1 to 174.89.19.254174.89.19.255254
21174.89.20.0/24174.89.20.1 to 174.89.20.254174.89.20.255254
22174.89.21.0/24174.89.21.1 to 174.89.21.254174.89.21.255254
23174.89.22.0/24174.89.22.1 to 174.89.22.254174.89.22.255254
24174.89.23.0/24174.89.23.1 to 174.89.23.254174.89.23.255254
25174.89.24.0/24174.89.24.1 to 174.89.24.254174.89.24.255254
26174.89.25.0/24174.89.25.1 to 174.89.25.254174.89.25.255254
27174.89.26.0/24174.89.26.1 to 174.89.26.254174.89.26.255254
28174.89.27.0/24174.89.27.1 to 174.89.27.254174.89.27.255254
29174.89.28.0/24174.89.28.1 to 174.89.28.254174.89.28.255254
30174.89.29.0/24174.89.29.1 to 174.89.29.254174.89.29.255254
31174.89.30.0/24174.89.30.1 to 174.89.30.254174.89.30.255254
32174.89.31.0/24174.89.31.1 to 174.89.31.254174.89.31.255254
33174.89.32.0/24174.89.32.1 to 174.89.32.254174.89.32.255254
34174.89.33.0/24174.89.33.1 to 174.89.33.254174.89.33.255254
35174.89.34.0/24174.89.34.1 to 174.89.34.254174.89.34.255254
36174.89.35.0/24174.89.35.1 to 174.89.35.254174.89.35.255254
37174.89.36.0/24174.89.36.1 to 174.89.36.254174.89.36.255254
38174.89.37.0/24174.89.37.1 to 174.89.37.254174.89.37.255254
39174.89.38.0/24174.89.38.1 to 174.89.38.254174.89.38.255254
40174.89.39.0/24174.89.39.1 to 174.89.39.254174.89.39.255254
41174.89.40.0/24174.89.40.1 to 174.89.40.254174.89.40.255254
42174.89.41.0/24174.89.41.1 to 174.89.41.254174.89.41.255254
43174.89.42.0/24174.89.42.1 to 174.89.42.254174.89.42.255254
44174.89.43.0/24174.89.43.1 to 174.89.43.254174.89.43.255254
45174.89.44.0/24174.89.44.1 to 174.89.44.254174.89.44.255254
46174.89.45.0/24174.89.45.1 to 174.89.45.254174.89.45.255254
47174.89.46.0/24174.89.46.1 to 174.89.46.254174.89.46.255254
48174.89.47.0/24174.89.47.1 to 174.89.47.254174.89.47.255254
49174.89.48.0/24174.89.48.1 to 174.89.48.254174.89.48.255254
50174.89.49.0/24174.89.49.1 to 174.89.49.254174.89.49.255254
51174.89.50.0/24174.89.50.1 to 174.89.50.254174.89.50.255254
52174.89.51.0/24174.89.51.1 to 174.89.51.254174.89.51.255254
53174.89.52.0/24174.89.52.1 to 174.89.52.254174.89.52.255254
54174.89.53.0/24174.89.53.1 to 174.89.53.254174.89.53.255254
55174.89.54.0/24174.89.54.1 to 174.89.54.254174.89.54.255254
56174.89.55.0/24174.89.55.1 to 174.89.55.254174.89.55.255254
57174.89.56.0/24174.89.56.1 to 174.89.56.254174.89.56.255254
58174.89.57.0/24174.89.57.1 to 174.89.57.254174.89.57.255254
59174.89.58.0/24174.89.58.1 to 174.89.58.254174.89.58.255254
60174.89.59.0/24174.89.59.1 to 174.89.59.254174.89.59.255254
61174.89.60.0/24174.89.60.1 to 174.89.60.254174.89.60.255254
62174.89.61.0/24174.89.61.1 to 174.89.61.254174.89.61.255254
63174.89.62.0/24174.89.62.1 to 174.89.62.254174.89.62.255254
64174.89.63.0/24174.89.63.1 to 174.89.63.254174.89.63.255254
65174.89.64.0/24174.89.64.1 to 174.89.64.254174.89.64.255254
66174.89.65.0/24174.89.65.1 to 174.89.65.254174.89.65.255254
67174.89.66.0/24174.89.66.1 to 174.89.66.254174.89.66.255254
68174.89.67.0/24174.89.67.1 to 174.89.67.254174.89.67.255254
69174.89.68.0/24174.89.68.1 to 174.89.68.254174.89.68.255254
70174.89.69.0/24174.89.69.1 to 174.89.69.254174.89.69.255254
71174.89.70.0/24174.89.70.1 to 174.89.70.254174.89.70.255254
72174.89.71.0/24174.89.71.1 to 174.89.71.254174.89.71.255254
73174.89.72.0/24174.89.72.1 to 174.89.72.254174.89.72.255254
74174.89.73.0/24174.89.73.1 to 174.89.73.254174.89.73.255254
75174.89.74.0/24174.89.74.1 to 174.89.74.254174.89.74.255254
76174.89.75.0/24174.89.75.1 to 174.89.75.254174.89.75.255254
77174.89.76.0/24174.89.76.1 to 174.89.76.254174.89.76.255254
78174.89.77.0/24174.89.77.1 to 174.89.77.254174.89.77.255254
79174.89.78.0/24174.89.78.1 to 174.89.78.254174.89.78.255254
80174.89.79.0/24174.89.79.1 to 174.89.79.254174.89.79.255254
81174.89.80.0/24174.89.80.1 to 174.89.80.254174.89.80.255254
82174.89.81.0/24174.89.81.1 to 174.89.81.254174.89.81.255254
83174.89.82.0/24174.89.82.1 to 174.89.82.254174.89.82.255254
84174.89.83.0/24174.89.83.1 to 174.89.83.254174.89.83.255254
85174.89.84.0/24174.89.84.1 to 174.89.84.254174.89.84.255254
86174.89.85.0/24174.89.85.1 to 174.89.85.254174.89.85.255254
87174.89.86.0/24174.89.86.1 to 174.89.86.254174.89.86.255254
88174.89.87.0/24174.89.87.1 to 174.89.87.254174.89.87.255254
89174.89.88.0/24174.89.88.1 to 174.89.88.254174.89.88.255254
90174.89.89.0/24174.89.89.1 to 174.89.89.254174.89.89.255254
91174.89.90.0/24174.89.90.1 to 174.89.90.254174.89.90.255254
92174.89.91.0/24174.89.91.1 to 174.89.91.254174.89.91.255254
93174.89.92.0/24174.89.92.1 to 174.89.92.254174.89.92.255254
94174.89.93.0/24174.89.93.1 to 174.89.93.254174.89.93.255254
95174.89.94.0/24174.89.94.1 to 174.89.94.254174.89.94.255254
96174.89.95.0/24174.89.95.1 to 174.89.95.254174.89.95.255254
97174.89.96.0/24174.89.96.1 to 174.89.96.254174.89.96.255254
98174.89.97.0/24174.89.97.1 to 174.89.97.254174.89.97.255254
99174.89.98.0/24174.89.98.1 to 174.89.98.254174.89.98.255254
100174.89.99.0/24174.89.99.1 to 174.89.99.254174.89.99.255254
101174.89.100.0/24174.89.100.1 to 174.89.100.254174.89.100.255254
102174.89.101.0/24174.89.101.1 to 174.89.101.254174.89.101.255254
103174.89.102.0/24174.89.102.1 to 174.89.102.254174.89.102.255254
104174.89.103.0/24174.89.103.1 to 174.89.103.254174.89.103.255254
105174.89.104.0/24174.89.104.1 to 174.89.104.254174.89.104.255254
106174.89.105.0/24174.89.105.1 to 174.89.105.254174.89.105.255254
107174.89.106.0/24174.89.106.1 to 174.89.106.254174.89.106.255254
108174.89.107.0/24174.89.107.1 to 174.89.107.254174.89.107.255254
109174.89.108.0/24174.89.108.1 to 174.89.108.254174.89.108.255254
110174.89.109.0/24174.89.109.1 to 174.89.109.254174.89.109.255254
111174.89.110.0/24174.89.110.1 to 174.89.110.254174.89.110.255254
112174.89.111.0/24174.89.111.1 to 174.89.111.254174.89.111.255254
113174.89.112.0/24174.89.112.1 to 174.89.112.254174.89.112.255254
114174.89.113.0/24174.89.113.1 to 174.89.113.254174.89.113.255254
115174.89.114.0/24174.89.114.1 to 174.89.114.254174.89.114.255254
116174.89.115.0/24174.89.115.1 to 174.89.115.254174.89.115.255254
117174.89.116.0/24174.89.116.1 to 174.89.116.254174.89.116.255254
118174.89.117.0/24174.89.117.1 to 174.89.117.254174.89.117.255254
119174.89.118.0/24174.89.118.1 to 174.89.118.254174.89.118.255254
120174.89.119.0/24174.89.119.1 to 174.89.119.254174.89.119.255254
121174.89.120.0/24174.89.120.1 to 174.89.120.254174.89.120.255254
122174.89.121.0/24174.89.121.1 to 174.89.121.254174.89.121.255254
123174.89.122.0/24174.89.122.1 to 174.89.122.254174.89.122.255254
124174.89.123.0/24174.89.123.1 to 174.89.123.254174.89.123.255254
125174.89.124.0/24174.89.124.1 to 174.89.124.254174.89.124.255254
126174.89.125.0/24174.89.125.1 to 174.89.125.254174.89.125.255254
127174.89.126.0/24174.89.126.1 to 174.89.126.254174.89.126.255254
128174.89.127.0/24174.89.127.1 to 174.89.127.254174.89.127.255254

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.